Integrated touch screens

ABSTRACT

Integrated touch screens are provided including drive lines formed of grouped-together circuit elements of a thin film transistor layer and sense lines formed between a color filter layer and a material layer that modifies or generates light. The common electrodes (Vcom) in the TFT layer can be grouped together during a touch sensing operation to form drive lines. Sense lines can be formed on an underside of a color filter glass, and a liquid crystal region can be disposed between the color filter glass and the TFT layer. Placing the sense lines on the underside of the color filter glass, i.e., within the display pixel cell, can provide a benefit of allowing the color filter glass to be thinned after the pixel cells have been assembled, for example.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/456,831, filed Aug. 11, 2014, which is a divisional of applicationSer. No. 12/976,997, filed Dec. 22, 2010 (now U.S. Pat. No. 8,804,056,issued Aug. 12, 2014), the contents of which are incorporated byreference herein in their entirety for all purposes.

FIELD OF THE DISCLOSURE

This relates generally to integrated touch screens, and moreparticularly, to integrated touch screens including drive lines formedof grouped-together circuit elements of a thin film transistor layer andsense lines formed between a color filter layer and a material layerthat modifies or generates light.

BACKGROUND OF THE DISCLOSURE

Many types of input devices are presently available for performingoperations in a computing system, such as buttons or keys, mice,trackballs, joysticks, touch sensor panels, touch screens and the like.Touch screens, in particular, are becoming increasingly popular becauseof their ease and versatility of operation as well as their decliningprice. Touch screens can include a touch sensor panel, which can be aclear panel with a touch-sensitive surface, and a display device such asa liquid crystal display (LCD) that can be positioned partially or fullybehind the panel so that the touch-sensitive surface can cover at leasta portion of the viewable area of the display device. Touch screens canallow a user to perform various functions by touching the touch sensorpanel using a finger, stylus or other object at a location oftendictated by a user interface (UI) being displayed by the display device.In general, touch screens can recognize a touch and the position of thetouch on the touch sensor panel, and the computing system can theninterpret the touch in accordance with the display appearing at the timeof the touch, and thereafter can perform one or more actions based onthe touch. In the case of some touch sensing systems, a physical touchon the display is not needed to detect a touch. For example, in somecapacitive-type touch sensing systems, fringing electrical fields usedto detect touch can extend beyond the surface of the display, andobjects approaching near the surface may be detected near the surfacewithout actually touching the surface.

Capacitive touch sensor panels can be formed from a matrix of drive andsense lines of a substantially transparent conductive material, such asIndium Tin Oxide (ITO), often arranged in rows and columns in horizontaland vertical directions on a substantially transparent substrate. It isdue in part to their substantial transparency that capacitive touchsensor panels can be overlaid on a display to form a touch screen, asdescribed above. Some touch screens can be formed by integrating touchsensing circuitry into a display pixel stackup (i.e., the stackedmaterial layers forming the display pixels).

SUMMARY

The following description includes examples of integrated touch screensincluding drive lines formed of grouped-together circuit elements of athin film transistor layer and sense lines formed between a color filterlayer and a material layer that modifies or generates light. In someexamples, the touch screen can be an in-plane switching (IPS) liquidcrystal display (LCD), fringe field switching (FFS), advanced fringefield switching (AFFS), etc. The common electrodes (Vcom) in the TFTlayer can be grouped together during a touch sensing operation to formdrive lines. Sense lines can be formed on an underside of a color filterglass, and a liquid crystal region can be disposed between the colorfilter glass and the TFT layer. Placing the sense lines on the undersideof the color filter glass, i.e., within the display pixel cell, canprovide a benefit of allowing the color filter glass to be thinned afterthe pixel cells have been assembled, for example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C illustrate an example mobile telephone, an example mediaplayer, and an example personal computer that each include an exampletouch screen according to embodiments of the disclosure.

FIG. 2 is a block diagram of an example computing system thatillustrates one implementation of an example touch screen according toembodiments of the disclosure.

FIG. 3 illustrates example configurations of sense lines, drive lines,and other example structures of a touch screen according to embodimentsof the disclosure.

FIG. 3A illustrates an example display pixel stackup according toembodiments of the disclosure.

FIG. 4 illustrates a more detailed view of an example color filter glassincluding sense lines disposed on an underside of the color filter glassaccording to embodiments of the disclosure.

FIG. 5 illustrates an example color filter glass that includes anorganic coat formed over conductive wires according to embodiments ofthe disclosure.

FIG. 6 illustrates other example configurations of sense lines, drivelines, and other example structures of a touch screen according toembodiments of the disclosure.

FIG. 7 illustrates a more detailed view of another example color filterglass including sense lines disposed on an underside of the color filterglass according to embodiments of the disclosure.

FIG. 8 illustrates an example configuration of drive lines includingcircuit elements of a TFT layer of a touch screen according toembodiments of the disclosure.

FIG. 9 illustrates another example configuration of drive linesincluding circuit elements of a TFT layer of a touch screen according toembodiments of the disclosure.

FIG. 9A illustrates an example circuit of a TFT substrate according toembodiments of the disclosure.

FIG. 10 includes an example configuration of a color filter glassincluding contact pads connected to sense lines according to embodimentsof the disclosure.

FIG. 11 illustrates an example configuration of a TFT glass according toembodiments of the disclosure.

FIG. 12 illustrates another example configuration of a TFT glassaccording to embodiments of the disclosure.

FIG. 13 illustrates an example method of driving circuit elements of atouch screen in a display operation and in a touch sensing operationaccording to embodiments of the disclosure.

FIG. 14 illustrates another example configuration of a color filgerglass according to embodiments of the disclosure.

FIG. 15 illustrates another example configuration of a TFT glassaccording to embodiments of the disclosure.

DETAILED DESCRIPTION

In the following description of example embodiments, reference is madeto the accompanying drawings which form a part hereof, and in which itis shown by way of illustration specific embodiments in whichembodiments of the disclosure can be practiced. It is to be understoodthat other embodiments can be used and structural changes can be madewithout departing from the scope of the embodiments of this disclosure.

The following description includes examples of integrated touch screensincluding drive lines formed of grouped-together circuit elements of athin film transistor layer and sense lines formed between a color filterlayer and a material layer that modifies or generates light. In someexamples, the touch screen can be an in-plane switching (IPS) liquidcrystal display (LCD), fringe field switching (FFS), advanced fringefield switching (AFFS), etc. The common electrodes (Vcom) in the TFTlayer can be grouped together during a touch sensing operation to formdrive lines. Sense lines can be formed on an underside of a color filterglass, and a liquid crystal region can be disposed between the colorfilter glass and the TFT layer. Placing the sense lines on the undersideof the color filter glass, i.e., within the display pixel cell, canprovide a benefit of allowing the color filter glass to be thinned afterthe pixel cells have been assembled, for example.

During a display operation, in which an image is displayed on the touchscreen, the Vcom can serve as part of the display circuitry, forexample, by carrying a common voltage to create, in conjunction with apixel voltage on a pixel electrode, an electric field across the liquidcrystal. During a touch sensing operation, the a stimulation signal canbe applied to a group of Vcom that form a drive line. A sense signalbased on the stimulation signal can be received by the sense lines onthe underside of the color filter glass and processed by a touchprocessor to determine an amount and location of touch on the touchscreen.

FIGS. 1A-1C show example systems in which a touch screen according toembodiments of the disclosure may be implemented. FIG. 1A illustrates anexample mobile telephone 136 that includes a touch screen 124. FIG. 1Billustrates an example digital media player 140 that includes a touchscreen 126. FIG. 1C illustrates an example personal computer 144 thatincludes a touch screen 128. Touch screens 124, 126, and 128 can bebased on mutual capacitance. A mutual capacitance based touch system caninclude, for example, drive regions and sense regions, such as drivelines and sense lines. For example, drive lines can be formed in rowswhile sense lines can be formed in columns (e.g., orthogonal). Touchpixels can be formed at the intersections of the rows and columns.During operation, the rows can be stimulated with an AC waveform and amutual capacitance can be formed between the row and the column of thetouch pixel. As an object approaches the touch pixel, some of the chargebeing coupled between the row and column of the touch pixel can insteadbe coupled onto the object. This reduction in charge coupling across thetouch pixel can result in a net decrease in the mutual capacitancebetween the row and the column and a reduction in the AC waveform beingcoupled across the touch pixel. This reduction in the charge-coupled ACwaveform can be detected and measured by the touch sensing system todetermine the positions of multiple objects when they touch the touchscreen. In some embodiments, a touch screen can be multi-touch, singletouch, projection scan, full-imaging multi-touch, capacitive touch, etc.

FIG. 2 is a block diagram of an example computing system 200 thatillustrates one implementation of an example touch screen 220 accordingto embodiments of the disclosure. Computing system 200 could be includedin, for example, mobile telephone 136, digital media player 140,personal computer 144, or any mobile or non-mobile computing device thatincludes a touch screen. Computing system 200 can include a touchsensing system including one or more touch processors 202, peripherals204, a touch controller 206, and touch sensing circuitry (described inmore detail below). Peripherals 204 can include, but are not limited to,random access memory (RAM) or other types of memory or storage, watchdogtimers and the like. Touch controller 206 can include, but is notlimited to, one or more sense channels 208, channel scan logic 210 anddriver logic 214. Channel scan logic 210 can access RAM 212,autonomously read data from the sense channels and provide control forthe sense channels. In addition, channel scan logic 210 can controldriver logic 214 to generate stimulation signals 216 at variousfrequencies and phases that can be selectively applied to drive lines ofthe touch sensing circuitry of touch screen 220, as described in moredetail below. In some embodiments, touch controller 206, touch processor202 and peripherals 204 can be integrated into a single applicationspecific integrated circuit (ASIC).

Computing system 200 can also include a host processor 228 for receivingoutputs from touch processor 202 and performing actions based on theoutputs. For example, host processor 228 can be connected to programstorage 232 and a display controller, such as an LCD driver 234. The LCDdriver 234 can provide voltages on select (gate) lines to each pixeltransistor and can provide data signals along data lines to these sametransistors to control the pixel display image as described in moredetail below. Host processor 228 can use LCD driver 234 to generate animage on touch screen 220, such as an image of a user interface (UI),and can use touch processor 202 and touch controller 206 to detect atouch on or near touch screen 220, such a touch input to the displayedUI. The touch input can be used by computer programs stored in programstorage 232 to perform actions that can include, but are not limited to,moving an object such as a cursor or pointer, scrolling or panning,adjusting control settings, opening a file or document, viewing a menu,making a selection, executing instructions, operating a peripheraldevice connected to the host device, answering a telephone call, placinga telephone call, terminating a telephone call, changing the volume oraudio settings, storing information related to telephone communicationssuch as addresses, frequently dialed numbers, received calls, missedcalls, logging onto a computer or a computer network, permittingauthorized individuals access to restricted areas of the computer orcomputer network, loading a user profile associated with a user'spreferred arrangement of the computer desktop, permitting access to webcontent, launching a particular program, encrypting or decoding amessage, and/or the like. Host processor 228 can also perform additionalfunctions that may not be related to touch processing.

Touch screen 220 can include touch sensing circuitry that can include acapacitive sensing medium having a plurality of drive lines 222 and aplurality of sense lines 223. It should be noted that the term “lines”is a sometimes used herein to mean simply conductive pathways, as oneskilled in the art will readily understand, and is not limited toelements that are strictly linear, but includes pathways that changedirection, and includes pathways of different size, shape, materials,etc, and multiple electrically conductive circuit elements that can beelectrically connected to form a single electrically conductive pathway.Drive lines 222 can be driven by stimulation signals 216 from driverlogic 214 through drive interfaces 224 a and 224 b, and resulting sensesignals 217 generated in sense lines 223 can be transmitted through asense interface 225 to sense channels 208 (also referred to as an eventdetection and demodulation circuit) in touch controller 206. Thestimulation signal may be an alternating current (AC) waveform. In thisway, drive lines and sense lines can be part of the touch sensingcircuitry that can interact to form capacitive sensing nodes, which canbe thought of as touch picture elements (touch pixels), such as touchpixels 226 and 227. This way of understanding can be particularly usefulwhen touch screen 220 is viewed as capturing an “image” of touch. Inother words, after touch controller 206 has determined an amount oftouch detected at each touch pixel in the touch screen, the pattern oftouch pixels in the touch screen at which a touch occurred can bethought of as an “image” of touch (e.g. a pattern of fingers touchingthe touch screen).

Structures and operations of various example embodiments of integratedtouch screens will now be described with reference to FIGS. 3-15.

FIG. 3 illustrates example embodiments of sense lines, drive lines, andother example structures of touch screen. FIG. 3 shows a more detailedview of a lower left hand portion of touch screen 220 along line “A”shown in FIG. 2. In the example embodiment shown in FIG. 3, each senseline 223 includes multiple conductive wires 301, e.g., five conductivewires in this example embodiment. Conductive wires 301 are disposed onthe underside of a color filter glass 303, between the color filterglass and the TFT glass. The color filter glass 303 can include aplurality of color filters 305. In this example embodiment, colorfilters 305 each include three colors, blue (B), green (G), and red (R),such as in an RGB display. Each conductive wire 301 is positionedbetween two columns of color filters 305. In this example, the spacebetween the columns of the color filters can be widened to accommodatethe conductive wire. In the example shown, five conductive wires 301 ofeach sense line 223 can be connected to a contact pad 307 thatconductively connects the conductive wires of the sense line and allowseach group of five conductive wires to operate as a single sense line.Contact pads 307 can be electrically connected to, for example, sensechannels 208 of touch controller 206 shown in FIG. 2, so that sensesignals 217 received by each sense line 223 can be processed by thetouch controller.

FIG. 3 also shows a TFT glass 309, on which can be formed circuitelements 311. Circuit elements 311 can be, for example, multi-functioncircuit elements that operate as part of the display circuitry of thetouch screen and also as part of the touch sensing circuitry of thetouch screen. In some embodiments, circuit elements 311 can besingle-function circuit elements that operate only as part of the touchsensing system. In addition to circuit elements 311, other circuitelements (not shown) can be formed on TFT glass 309, such astransistors, capacitors, conductive vias, data lines, gate lines, etc.Circuit elements 311 and the other circuit elements formed on TFT glass309 can operate together to perform various display functionalityrequired for the type of display technology used by touch screen 220, asone skilled in the art would understand. The circuit elements caninclude, for example, elements that can exist in conventional LCDdisplays. It is noted that circuit elements are not limited to wholecircuit components, such a whole capacitor, a whole transistor, etc.,but can include portions of circuitry, such as only one of the twoplates of a parallel plate capacitor.

Some of the circuit elements 311 can be electrically connected togethersuch that the circuit elements 311 and their interconnections togetherform drive lines 222. Various example methods of connecting togethercircuit elements 311 to form drive lines 222 will be discussed in moredetail in reference to FIGS. 8-9. Some of the circuit elements 311 thatlie between drive lines 222 can serve as a buffer region 313. Onepurpose of the buffer region 313 can be to separate drive lines 222 fromone another to reduce or to prevent cross talk and stray capacitanceeffects. Circuit elements 311 in buffer region 313 can, for example, beunconnected from drive lines 222. In various embodiments, some or all ofthe circuit elements 311 in buffer region 313 can be, for example,electrically connected to each other, electrically unconnected from eachother, maintained at a fixed voltage during a touch sensing operation,maintained at a floating potential during a touch sensing operation,etc. The example configurations of sense lines 223 and drive lines 222shown in FIG. 3 can be laid out as shown in FIG. 2 as an overlappingorthogonal grid to form touch pixels 226 and 227, for example. Althoughnot illustrated in FIG. 3, it is understood that first and secondpolarizers can be provided, the first polarizer can be adjacent the TFTglass and the second polarizer can be adjacent the color filter glasssuch that the TFT glass and the color filter glass are disposed betweenthe first and second polarizers.

FIG. 3 also shows a pixel material 315 disposed between TFT glass 309and color filtered glass 303. Pixel material 315 is shown in FIG. 3 asseparate volumn regions or cells above the circuit elements 311. Forexample, when the pixel material is a liquid crystal, these volumnregions or cells are meant to illustrate regions of the liquid crystalcontrolled by the electric field produced by the pixel electrode andcommon electrode of the volume region or cell under consideration. Pixelmaterial 315 can be a material that, when operated on by the displaycircuitry of touch screen 220, can generate or control an amount, color,etc., of light produced by each display pixel. For example, in an LCDtouch screen, pixel material 315 can be formed of liquid crystal, witheach display pixel controlling a volumn region or cell of the liquidcrystal. In this case, for example, various methods exist for operatingliquid crystal in a display operation to control the amount of lightemanating from each display pixel, e.g., applying an electric field in aparticular direction depending on the type of LCD technology employed bythe touch screen. In an in-plane switching (IPS), fringe field swithing(FFS), and advanced fringe field switching (AFFS) LCD displays, forexample, electrical fields between pixel electrodes and commonelectrodes (Vcom) disposed on the same side of the liquid crystal canoperate on the liquid crystal material to control the amount of lightfrom a backlight that passes through the display pixel. In an OLED(organic light emitting diode) display, for example, pixel material 315can be, for example, an organic material in each pixel that generateslight when a voltage is applied across the material. One skilled in theart would understand that various pixel materials can be used, dependingon the type of display technology of the touch screen.

FIG. 3A illustrates an enlarged view of a display pixel (as for example,a particular R, B, or G sub-pixel). As may be seen in FIG. 3A, there canbe provided a first substrate 325 (such as the TFT glass 309 of FIG. 3),a second substrate 327 (such as the color filter glass 303 of FIG. 3), afirst polarizer 329 and a second polarizer 331. The first polarizer 329can be disposed adjacent the first substrate 325, and the secondpolarizer 331 can be disposed adjacent the second substrate 327. Onedisplay pixel of the first substrate 325 is shown greatly enlarged forpurposes of illustration. A TFT 335 can have a gate 337, a source 339connected to a data line 341, and a drain 343 connected to pixelelectrode 345. Common electrode 347 can be disposed adjacent the pixelelectrode 345 and can be connected to a common electrode conductive line349. Layers of diectric material 351 a, 351 b and 351 c can be disposedas shown in FIG. 3A to separate electrodes from one another. FIG. 3Aalso illustrates gate insulation layer 353. An electrical fringe fieldbetween the pixel electrode 345 and the common electrode 347 can controlthe pixel material disposed between the first and second substratesduring the display operation in order to provide a display image.

FIG. 4 illustrates a more detailed view of color filter glass 303. FIG.4 includes color filters 305, conductive wires 301, which form senselines 203. Conductive wires 301 can be, for example, metal lines such asaluminum, etc. In this regard conductive wires 301 can be positionedbehind a black mask 401 so that the conductive wires are not visible toa user. Therefore conductive wires 301 need not be transparentconductors. However, in some example embodiments, conductive wires 301can be transparent metal. Although in the example embodiment shown inFIG. 4 the spacing between the columns of color filters 305 can bewidened to accommodate conductive wires 301, in some embodiments thespacing can be different, including equal spacing between the colorfilters.

FIG. 5 illustrates an example embodiment that includes an organic coat501 that has been formed over conductive wires 301. In other words,conductive wires 301 can be formed on the underside of color filterglass 303, and then organic coat 501 can be formed on conductive wires301, such that the conductive wires are disposed between color filterglass 303 and organic coat 501. Organic coat 501 can be formed of amaterial that can protect the conductive wires from exposure tochemicals, from physical abrasion, etc.

FIG. 6 illustrates another example embodiment showing another exampleconfiguration of sense lines 223. As in the example shown in FIG. 3, theexample shown in FIG. 6 is a perspective view along line “A” shown inFIG. 2. In the example embodiment shown in FIG. 6, each of the senselines 223 can include a conductive mesh 601. Conductive mesh 601 can beformed of, for example, metal wires, metal strips, etc., that are formedon the underside of color filter glass 303. Conductive mesh 601 can be,for example, a conductive orthogonal grid, the conductive lines of whichare disposed between individual color filters 305.

Sense line 223, formed of conductive mesh 601, can be conductivelyconnected to contact pad 307 such that a sense signal received by thesense line can be transmitted to touch controller 206 for processing.Similar to the previous embodiment, the portion of touch screen 220shown in example embodiment in FIG. 6 includes drive lines 222 andbuffer regions 313, each of which can be formed of circuit elements 311that have been grouped together either operationally or physically toperform their respective functions. In a touch sensing operation,stimulation signals applied to drive lines 222 can allow touches to besensed by sense lines 223 in the areas of various touch pixels, such astouch pixels 226 and 227. The example embodiment shown in FIG. 6 alsoincludes pixel material 315, similar to the example embodiment shown inFIG. 3.

FIG. 7 illustrates a more detailed view of color filter glass 303 shownin the example embodiment FIG. 6. FIG. 7 includes color filters 305 andconductive mesh 601, which form sense lines 203. Conductive mesh 601 canbe, for example, formed of non-transparent metal lines such as aluminum,etc. In this regard conductive mesh 601 can be positioned behind a blackmask 701 so that the conductive mesh is not visible to a user.Therefore, in this embodiment, the conductive mesh 601 need not be madeof transparent conductors. However, in some example embodiments,conductive mesh 601 can be transparent metal.

FIG. 8 illustrates a more detailed view of an example configuration ofdrive lines 222 and buffer regions 313 according to various embodiments.In this example embodiment, circuit elements 311 can include commonelectrodes 801. Common electrodes 801 can be operated as multi-functioncircuit elements that can operate as part of the display circuitry in adisplay operation and can operate as part of the touch sensing circuitryin a touch sensing operation of the touch screen. Common electrodes 801can be electrically connected together with conductive lines 803, toform the required regions such as regions that operate as drive lines222 and regions that operate as buffer regions 313. In this exampleembodiment, common electrodes functional region can be physicallyconnected with fixed conductive lines. In other words, the commonelectrodes in each region can be permanently connected through thephysical design of the touch screen. In other words, common electrodes801 can be grouped together to form drive lines. Grouping multi-functioncircuit elements of display pixels can include operating themulti-function circuit elements of the display pixels together toperform a common function of the group. Grouping into functional regionsmay be accomplished through one or a combination of approaches, forexample, the structural configuration of the system (e.g., physicalbreaks and bypasses, voltage line configurations), the operationalconfiguration of the system (e.g., switching circuit elements on/off,changing voltage levels and/or signals on voltage lines), etc.

Stimulation signals can be applied to drive lines 222 through drive leadlines 805. For example, drive lead lines can be electrically connectedto driver logic 214, which can provide the stimulation signals duringthe touch sensing operation. Buffer region 313 can be connected to abuffer lead line 807, which can be connected to a buffer operator (notshown).

In the example shown in FIG. 8, each common electrode (Vcom) 801 canserve as a multi-function circuit element that can operate as displaycircuitry of the display system of touch screen 220 and can also operateas touch sensing circuitry of the touch sensing system. In this example,each common electrode 801 can operate as a common electrode of thedisplay circuitry of the touch screen, and can also operate togetherwhen grouped with other common electrodes as touch sensing circuitry ofthe touch screen. For example, a group of common electrodes 801 canoperate together as a part of a drive line of the touch sensingcircuitry during the touch sensing operation. Other circuit elements oftouch screen 220 can form part of the touch sensing circuitry by, forexample, electrically connecting together common electrodes 801 of aregion, switching electrical connections, etc. Each display pixel caninclude a common electrode 801, which can be a circuit element of thedisplay system circuitry in the pixel stackup (i.e., the stackedmaterial layers forming the display pixels) of the display pixels ofsome types of conventional LCD displays, e.g., fringe field switching(FFS) displays, that can operate as part of the display system todisplay an image.

In general, each of the touch sensing circuit elements may be either amulti-function circuit element that can form part of the touch sensingcircuitry and can perform one or more other functions, such as formingpart of the display circuitry, or may be a single-function circuitelement that can operate as touch sensing circuitry only. Similarly,each of the display circuit elements may be either a multi-functioncircuit element that can operate as display circuitry and perform one ormore other functions, such as operating as touch sensing circuitry, ormay be a single-function circuit element that can operate as displaycircuitry only. Therefore, in some embodiments, some of the circuitelements in the display pixel stackups can be multi-function circuitelements and other circuit elements may be single-function circuitelements. In other embodiments, all of the circuit elements of thedisplay pixel stackups may be single-function circuit elements.

In the embodiment shown in FIG. 9, the circuit elements used to formdrive lines, Vcom 901 in this example, can be physically connectedtogether on the TFT glass through conductive lines 903 to formindividual rows of connected together Vcom 901. The individual rows ofVcom, i.e., Vcom drive rows 905, can be connected together with otherVcom drive rows in the periphery using contact pads 907. In thisexample, each drive line 222 can be formed through fixed electricalconnections.

FIG. 9A illustrates a more detailed view of the of the TFT glasssubstrate previously illustrated in FIGS. 3, 6, 8 and 9. It isunderstood that the pixel electrodes, gate lines, data lines, TFTelements, and common electrode conductive lines connecting together thecommon electrodes are also present in FIGS. 3, 6, 8 and 9, but have beenomitted for simplicity of illustration. Thus, as seen in FIG. 9A, gatelines 925 extend in a row (horizontal) direction and data lines 927extend in a column (vertical) direction. The gate lines can be connectedto gates of transistors 929 (for example, thin film transistors, TFTs)and control (e.g., turn on) these transistors to permit data from thedata lines 927 to be applied to pixel electrodes 931 during a displayoperation. During the display operation, common electrodes 901 can beheld at a preset voltage. FIG. 9A also shows conductive lines 903interconnecting common electrodes 901 along the row and columndirections. An electrical field can be formed by the difference involtage between pixel electrode 931 and its corresponding commonelectrode 901 and this electric field can control the pixel materialdisposed above the first substrate (disposed between the first andsecond substrates). A pixel can be formed at each crossing of gate line925 and data line 927 and comprises the pixel electrode 931 and itscorresponding common electrode 901.

FIGS. 10 and 11 illustrate an example color filter glass design and anexample TFT design, respectively, according to various embodiments. FIG.10 includes an example configuration of multiple sense lines 223, eachincluding multiple conductive wires such as conductive wires 301,connected to multiple contact pads, such as contact pad 311. For thesake of clarity, individual color filters are not shown in FIG. 10 Inthis example embodiment, conductive wires 301 and contact pads 307 canbe formed on color filter glass 303 by, for example, physical vapordeposition (PVD).

FIG. 11 illustrates an example TFT glass according to various exampleembodiments. TFT glass 1101 can include various touch sensing circuitryand display circuitry. Touch sensing circuitry can include, for example,drive lines 222. In this example embodiment, each drive line 222 caninclude multiple Vcom drive rows 1103. In this example embodiment, eachVcom drive row 1103 in a drive line 222 can be connected to a singleconductive contact pad 1105 on the left side of the TFT glass, andconnected to a single contact pad 1105 on the right side of TFT glass.Contact pads 1105 can be connected through drive signal lines 1107 totouch controller 206 (FIG. 2) through a touch flex circuit 1109. In thisway, for example, multiple Vcom drive rows 1103 can be driven togetheras a single drive line 222 during a touch sensing operation. TFT glass1101 can also include integrated drivers 1111 that can drive the displaycircuitry, for example, using various display circuit elements such asgate lines, data lines, etc. Touch flex circuit 1109 can also beconnected to sense signal lines 1113, which can be connected to contactpads 307 on the color filter glass through conductive paste 1115.

FIG. 12 illustrates another example TFT glass design. FIG. 12 shows aTFT glass 1201 in which individual rows of Vcom are electricallyconnected together to form Vcom drive rows 1203. In other words, similarto the previous embodiment, each Vcom circuit element in Vcom drive row1203 is permanently connected to the other Vcom in the drive row.However, in the example embodiment shown in FIG. 12, each individualVcom drive row 1203 can be connected to a Vcom driver 1205 in theperiphery of TFT glass 1201. Vcom driver 1205 can operate the Vcom driverows 1203 in each drive line 222 to generate the same stimulationsignals on each individual Vcom drive row 1203 of each drive line 222during a touch sensing operation. In other words, a first stimulationsignal can be applied to a first group of individual rows of Vcom, and asecond stimulation signal can be applied to a second group of individualrows of Vcom. In this way, for example, a group of multiple Vcom driverows 1203 can be operated together as a single drive line 222 eventhough the individual Vcom drive rows themselves are not connected toeach other through fixed electrical connections.

Likewise, during a display operation of the touch screen, integratedgate drivers 1207 can operate the individual Vcom drive rows 1203 aspart of the display circuitry to display an image on the touch screen.Therefore, in this example embodiment, the individual Vcom drive rows1203 can be grouped together or operated individually as neededdepending on the operation of the touch screen.

FIG. 13 illustrates an example method of driving the circuit elements ofthe touch screen in the display operation and in the touch sensingoperation. This example method can apply to an operation of a touchscreen including the design of TFT glass 1201 of FIG. 12, for example.In this example embodiment, the display operation in which an image isdisplayed and the touch sensing operation in which touch is sensed canoccur concurrently by operating different portions of the touch screendifferently, that is, one group of circuit elements can be operated asdisplay circuitry to display an image while, at the same time, anothergroup of the circuit elements can be operated as touch sensing circuitryto sense a touch.

In a first time period 1301, integrated gate driver 1207, along withother display circuitry, can update a first group 1303 of circuitelements, e.g., an individual row of display pixels, to display a lineof an image on the touch screen. For example, integrated gate driver1207 can apply a common voltage to the Vcom in the first row of displaypixels. Concurrently, in first time period 1301, Vcom driver 1205 canapply a stimulation signal to a first drive line 1305 that includes asecond group 1307 of the circuit elements. Applying the stimulationsignal can include, for example, applying the same stimulation signal toeach of the individual Vcom drive rows 1203 in the first drive line 222.Because the image scanning row currently being scanned by integratedgate driver 1207 is not located in first drive line 1305, the Vcom driverows 1203 being used for updating the displayed image do not overlapwith the Vcom drive rows 1203 used for touch sensing as a drive line.

A second time period 1302 shows a third group 1309 of circuit elementscan be operated as display circuitry, e.g., integrated gate driver 1207can apply a common voltage to the Vcom in a third row of display pixels.The common voltage applied to the Vcom in the third row can be, forexample, of an opposite polarity to the common voltage applied to theVcom in the first row of display pixels. Concurrently, in second timeperiod 1302, Vcom driver 1205 can apply a stimulation signal to a seconddrive line 1311 that includes first group 1303 and additional rows ofVcom 1313. In this way, for example, display operation and touch sensingoperation can occur concurrently in an integrated touch screen.

In the example driving method shown in FIG. 13, display updating can bedone on a row by row basis for individual Vcom drive rows 1203. In someembodiments, integrated gate driver 1207 can change the Vcom polarity ona row by row basis as well. For example, for each row of display pixelintegrated gate driver 1207 can operate to change the polarity of Vcom,switch the gates of the row of display pixels to an “on” state, writedata into each display pixel, and switch the gates to an “off” state.When different rows of Vcom are operated to perform touch sensingconcurrently with display updating, as in this example embodiment, it isnoted that in the touch sensing groups of circuit elements no data isbeing written into the display pixels in the rows of pixels in the driveline because the gate lines of these rows of display pixels are in the“off” state.

FIG. 14 illustrates another example embodiment of sense lines 223. FIG.14 illustrates a color filter glass 303 that includes sense lines 223formed of a transparent conductor, such as indium tin oxide (ITO), onthe underside of color filter glass 303. The ITO can be deposited on theunderside of color filter glass 303 to cover a contiguous area includingcovering color filters 305. FIG. 14 also illustrates ground regions 1401between sense lines 223. Ground regions 1401 can be formed oftransparent conductor, such as ITO formed on the underside of colorfilter glass 303 and electrically separated from the sense lines oneither side of each sense line. Ground regions 1401 can be connected to,for example, a ground or virtual ground in the periphery of the panel.Positioning ground regions between sense regions can help reduceinterference in some embodiments.

FIG. 15 illustrates an example TFT glass design, TFT glass 1501. In thisexample, TFT glass 1501 can include various touch sensing circuitry anddisplay circuitry. Touch sensing circuitry can include, for example,drive lines 222. In this example embodiment, each drive line 222 caninclude multiple Vcom drive rows 1503. In this example embodiment, eachVcom drive row 1503 in a drive line 222 can be connected to a singleconductive contact pad 1505 on the left side of the TFT glass, andconnected to a single contact pad 1105 on the right side of TFT glass.Contact pads 1505 can be connected through drive signal lines 1507 totouch controller 206 through a touch flex circuit 1509. In this way, forexample, multiple Vcom drive rows 1503 can be driven together as asingle drive line 222 during a touch sensing operation. TFT glass 1501can also include integrated drivers 1511 that can drive the displaycircuitry, for example, using various display circuit elements such asgate lines, data lines, etc. Touch flex circuit 1509 can also beconnected to sense signal lines 1513, which can be connected to contactpads 307 on the color filter glass through conductive paste 1515.

In FIGS. 3, 6, 8 and 9, each row of display pixels is illustrated ashaving a separate common electrode for each display pixel. These commonelectrodes (for example, circuit elements 311 of FIGS. 3 and 6, commonelectrode 801 of FIG. 8, and common electrode 901 of FIG. 9) mayhowever, not be physically distinct and separate structurescorresponding to each pixel electrode. In some embodiments the commonelectrodes that are electrically connected together across a particularrow, as for example, Vcom drive row 905 of FIG. 9, may be formed by asingle, continuous layer of conductive material, e.g., ITO. Further, asingle continuous layer of conductive material (ITO) may be used for anentire drive line 222 such as in FIG. 8 where the illustrated commonelectrodes within each drive line 222 are electrically connectedtogether along both rows (first direction) and columns (seconddirection, perpendicular to the first direction).

In addition, although example embodiments herein may describe thedisplay circuitry as operating during a display operation, and describethe touch sensing circuitry as operating during a touch sensingoperation, it should be understood that a display operation and a touchsensing operation may be operated at the same time, e.g., partially orcompletely overlap, or the display operation and touch phase may operateat different times. Also, although example embodiments herein describecertain circuit elements as being multi-function and other circuitelements as being single-function, it should be understood that thecircuit elements are not limited to the particular functionality inother embodiments. In other words, a circuit element that is describedin one example embodiment herein as a single-function circuit elementmay be configured as a multi-function circuit element in otherembodiments, and vice versa.

Although embodiments of this disclosure have been fully described withreference to the accompanying drawings, it is to be noted that variouschanges and modifications including, but not limited to, combiningfeatures of different embodiments, omitting a feature or features, etc.,as will be apparent to those skilled in the art in light of the presentdescription and figures.

For example, one or more of the functions of computing system 200described above can be performed by firmware stored in memory (e.g. oneof the peripherals 204 in FIG. 2) and executed by touch processor 202,or stored in program storage 232 and executed by host processor 228. Thefirmware can also be stored and/or transported within anycomputer-readable medium for use by or in connection with an instructionexecution system, apparatus, or device, such as a computer-based system,processor-containing system, or other system that can fetch theinstructions from the instruction execution system, apparatus, or deviceand execute the instructions. In the context of this document, a“computer-readable medium” can be any medium that can contain or storethe program for use by or in connection with the instruction executionsystem, apparatus, or device. The computer readable medium can include,but is not limited to, an electronic, magnetic, optical,electromagnetic, infrared, or semiconductor system, apparatus or device,a portable computer diskette (magnetic), a random access memory (RAM)(magnetic), a read-only memory (ROM) (magnetic), an erasableprogrammable read-only memory (EPROM) (magnetic), a portable opticaldisc such a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW, or flash memory suchas compact flash cards, secured digital cards, USB memory devices,memory sticks, and the like.

The firmware can also be propagated within any transport medium for useby or in connection with an instruction execution system, apparatus, ordevice, such as a computer-based system, processor-containing system, orother system that can fetch the instructions from the instructionexecution system, apparatus, or device and execute the instructions. Inthe context of this document, a “transport medium” can be any mediumthat can communicate, propagate or transport the program for use by orin connection with the instruction execution system, apparatus, ordevice. The transport readable medium can include, but is not limitedto, an electronic, magnetic, optical, electromagnetic or infrared wiredor wireless propagation medium.

Example embodiments may be described herein with reference to aCartesian coordinate system in which the x-direction and the y-directioncan be equated to the horizontal direction and the vertical direction,respectively. However, one skilled in the art will understand thatreference to a particular coordinate system is simply for the purpose ofclarity, and does not limit the direction of the elements to aparticular direction or a particular coordinate system. Furthermore,although specific materials and types of materials may be included inthe descriptions of example embodiments, one skilled in the art willunderstand that other materials that achieve the same function can beused. For example, it should be understood that a “metal layer” asdescribed in the examples below can be a layer of any electricallyconductive material.

In some embodiments, the drive lines and/or sense lines can be formed ofother elements including, for example other elements already existing intypical LCD displays (e.g., other electrodes, conductive and/orsemiconductive layers, metal lines that would also function as circuitelements in a typical LCD display, for example, carry signals, storevoltages, etc.), other elements formed in an LCD stackup that are nottypical LCD stackup elements (e.g., other metal lines, plates, whosefunction would be substantially for the touch sensing system of thetouch screen), and elements formed outside of the LCD stackup (e.g.,such as external substantially transparent conductive plates, wires, andother elements). For example, part of the touch sensing system caninclude elements similar to known touch panel overlays.

Although various embodiments are described with respect to displaypixels, one skilled in the art would understand that the term displaypixels can be used interchangeably with the term display sub-pixels inembodiments in which display pixels are divided into sub-pixels. Forexample, some embodiments directed to RGB displays can include displaypixels divided into red, green, and blue sub-pixels. In other words, insome embodiments, each sub-pixel can be a red (R), green (G), or blue(B) sub-pixel, with the combination of all three R, G and B sub-pixelsforming one color display pixel. One skilled in the art would understandthat other types of touch screen could be used. For example, in someembodiments, a sub-pixel may be based on other colors of light or otherwavelengths of electromagnetic radiation (e.g., infrared) or may bebased on a monochromatic configuration, in which each structure shown inthe figures as a sub-pixel can be a pixel of a single color.

What is claimed is:
 1. A capacitive touch screen comprising: a TFTlayer; a plurality of display pixels positioned on the TFT layer; eachdisplay pixel comprising a pixel electrode; one or more commonelectrodes positioned on the TFT layer; each pixel electrode operativelycoupled to one of the one or more common electrodes to provide a displayfunction in a display mode of operation; a color filter substrate; thethin film transistor (TFT) layer including a plurality of drive lines,wherein the drive lines are configured to transmit stimulation signals,the stimulation signals used to stimulate the capacitive touch screenfor the purpose of detecting touch input events, each drive lineconfigured from the one or more common electrodes in a touch sensingmode of operation; a pixel material disposed between the TFT layer andthe color filter substrate; and a plurality of sense lines disposed on aside of the color filter substrate facing the pixel material, whereinthe sense lines are configured to receive signals based on thestimulation signals transmitted by the drive lines and wherein the drivelines and the sense lines form a plurality of capacitive sensing nodes.2. The touch screen of claim 1, wherein each of the plurality of drivelines includes display pixels disposed along a first and second,different directions.
 3. The touch screen of claim 2, wherein during atouch sensing operation first stimulation signals are applied to a firstdrive line and second stimulation signals are applied to a second driveline.
 4. The touch screen of claim 2, wherein the one or more commonelectrodes are connected to display circuitry during a display mode ofoperation of the touch screen.
 5. The touch screen of claim 1, whereinelectric fields are applied to the pixel material during the displaymode of operation, the electric fields being based on voltages appliedto the one or more common electrodes.
 6. The touch screen of claim 1,wherein during a touch sensing operation first stimulation signals areapplied to a first drive line and second stimulation signals are appliedto a second drive line.
 7. The touch screen of claim 1, wherein eachsense line includes a plurality of conductive lines disposed on thecolor filter layer.
 8. The touch screen of claim 7, wherein each of theplurality of sense lines includes a conductive mesh disposed on thecolor filter substrate.
 9. The touch screen of claim 1, wherein thecolor filter substrate includes a black mask, and the plurality of senselines are non-transparent conductors disposed behind the black mask soas not to be visible to a user of the touch screen.
 10. A capacitivetouch screen including a plurality of display pixels, the touch screencomprising: a color filter layer disposed on a first substrate; aplurality of drive lines, disposed on a second substrate, the pluralityof drive lines carrying, during a touch sensing mode of operation,stimulation signals that are used to stimulate the touch screen for thepurpose of detecting touch and proximity events, each of the pluralityof drive lines configured from one or more common electrodes; a pixelmaterial disposed between the plurality of drive lines and the colorfilter layer; display circuitry that controls the pixel material, duringa display mode of operation, such that a controlled amount of light fromeach display pixel passes through the color filter layer to form animage; a plurality of sense lines that receive sense signals based onthe stimulation signals, the sense lines being disposed on a side of thefirst substrate facing the pixel material; and touch sensing circuitryconnected to receive the sense signals from the plurality of senselines.
 11. The touch screen of claim 10, wherein: the sense lines aredisposed on the color filter layer; and each of the plurality of drivelines includes groups of the plurality display pixels.
 12. The touchscreen of claim 11, wherein the color filter layer includes a pluralityof individual color filters, and the sense lines include conductivematerial disposed between individual color filters.
 13. The touch screenof claim 11, wherein the sense lines include non-transparent conductivematerial.
 14. The touch screen of claim 11, wherein the sense linesinclude transparent conductive material.
 15. The touch screen of claim11, further comprising an organic coating disposed on the sense lines.16. The touch screen of claim 10, wherein the pixel material includes alight modifying material.
 17. The touch screen of claim 10, wherein thepixel material includes a light generating material.
 18. A touch screenincluding a plurality of display pixels, the touch screen comprising: afirst substrate including a plurality display pixels having one or morecommon electrodes, each display pixel including a pixel electrode and aswitching element for connecting a data line to the pixel electrode todisplay an image on the touch screen during a display mode of operation;a plurality of drive lines disposed on the first substrate, each of theplurality of drive lines formed from the one or more common electrodes;the one or more common electrode receiving a common voltage during thedisplay mode of operation and a stimulation voltage during the touchsensing mode of operation; a second substrate including a color filterlayer; a pixel material disposed between the first and secondsubstrates; and a plurality of sense lines disposed between the colorfilter layer and the pixel material.
 19. The touch screen of claim 18,wherein the pixel electrodes of the plurality of display pixels and theone or more common electrodes are configured in an in-plane-switchingarrangement.
 20. The touch screen of claim 19, wherein the displaypixels are arranged along a first direction and along a seconddirection, perpendicular to the first direction, and wherein a pluralityof drive lines is formed by the plurality of groups of display pixels;and the sense lines are disposed along the second direction, crossingthe drive lines; wherein each intersection of one of the drive lineswith one of the sense lines forms a capacitive sensing node.
 21. Thetouch screen of claim 18, wherein the pixel material includes a lightmodifying material.
 22. The touch screen of claim 18, wherein the pixelmaterial includes a light generating material.
 23. The touch screen ofclaim 18, wherein the pixel electrodes of the plurality of displaypixels and the one or more common electrodes are configured in afringe-field-switching arrangement.